NEW YORK » Wall Street has managed an advance the hard way—zigzagging on a mix of earnings and economic news before closing moderately higher.

The major indexes changed course several times in yesterday's session, rising in response to Pfizer Inc.'s $68 billion planned acquisition of Wyeth, a deal that reassured investors that mergers could still take place in a recession. And the National Association of Realtors said existing homes rose rather than fell in December, stirring hopes that lower prices and falling interest rates are starting to erase at a glut of homes with “;for sale”; signs.

Wyeth fell 35 cents to $43.39, and Pfizer fell $1.80, or 10.3 percent, to $15.65.

But news from big companies weighed on the market. Downbeat comments from Caterpillar Inc. about the health of its business curbed the advance in the Dow Jones industrials. Home Depot Inc., another Dow component, also announced big job cuts. After the close of trading, chip maker Texas Instruments Inc. also announced job cuts—a total of 3,400, with 1,800 coming from layoffs.

The Dow rose 38.47, or 0.48 percent, to 8,116.03, after briefly moving into negative territory. The Standard & Poor's 500 index rose 4.62, or 0.56 percent, to 836.57, and the Nasdaq composite index rose 12.17, or 0.82 percent, to 1,489.46. The Russell 2000 index rose 5.70, or 1.28 percent, to 450.06.

Advancing issues outnumbered decliners by about 2 to 1 on the New York Stock Exchange, where volume came to 1.27 billion shares.

The dollar fell against other major currencies, while gold prices rose.

Light, sweet crude slipped 74 cents to settle at $45.73 on the New York Mercantile Exchange.

Bond prices fell yesterday as stocks rose. The yield on the benchmark 10-year Treasury note, which moves opposite its price, rose to 2.65 percent from 2.62 percent late Friday. The yield on the three-month T-bill, considered one of the safest investments, rose to 0.13 percent from 0.09 percent late Friday.